I'm in North Georgia. When I know we are going to have a big freeze like you are talking about I'll just drain the pool and wait until it warms up before I clean and fill it again. We used 4" PVC pipe going out of the back of the pool. I've never had an issue with the water inside the pipe...
I know nothing about geese but I do know about building a shallow pond. I sheet of plywood, and 2" x 12" for around the sides, then fiberglass and resin it. One thing we didn't think to do it sink the drain so now I have to sweep the excess water into the drain before I can clean it. We've got a...